Page 340 - Hacking Roomba

Chapter 14 — Putting Linux on Roomba 321

Listing 14-3 Continued

E: Ad=81(I) Atr=03(Int.) MxPS= 2 Ivl=255ms
T: Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 2 Spd=12 MxCh=
0
D: Ver= 1.10 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1
P: Vendor=0557 ProdID=2008 Rev= 3.00
S: Manufacturer=Prolific Technology Inc.
S: Product=USB-Serial Controller
C:* #Ifs= 1 Cfg#= 1 Atr=a0 MxPwr=100mA
I: If#= 0 Alt= 0 #EPs= 3 Cls=ff(vend.) Sub=00 Prot=00
Driver=serial
E: Ad=81(I) Atr=03(Int.) MxPS= 10 Ivl=1ms
E: Ad=02(O) Atr=02(Bulk) MxPS= 64 Ivl=0ms
E: Ad=83(I) Atr=02(Bulk) MxPS= 64 Ivl=0ms
root@OpenWrt:~# ipkg install lsusb
[...]
root@OpenWrt:~# lsusb
Bus 001 Device 001: ID 0000:0000
Bus 001 Device 004: ID 0557:2008 ATEN International Co., Ltd
UC-232A i
Serial Port [pl2303]

Scripting Language Control

Now you have an embedded Linux system with a functioning serial port. It is time to hook it
up to Roomba. Since the USB-to-serial adapter has the same RS-232 connector as the serial
tether of Chapter 3, just connect it to the adapter and Roomba and you’re good to go.

There have been efforts to get Java working in OpenWrt via the SableVM (http://
sablevm.org/) or JamVM (http://jamvm.sourceforge.net/), but getting a working
Java VM with the system classes in the remaining space of the WL-HDD would be difficult.
There are many alternatives to Java, however, and it would be interesting to try some of them.
Shell Script Control
Linux supports many ways of dealing with serial ports. Unix-like operating systems treat
everything as files, even devices such as serial ports. This level of abstraction enables you to
deal with almost any device in any language, all just by opening files. Need to format a disk?
Open /dev/hdd. Need to play an audio file? Send your WAV file to /dev/audio. You can
even control Roomba from the command line:
% printf “\x89\x00\xc8\x80\x00” > /dev/usb/tts/0 # DRIVE
straight at 200 mm/s

(You use \x89 to send bytes using hexadecimal codes.)